Semi-automatic shotgun

ABSTRACT

In the particular embodiment of the invention described herein, a semi-automatic shotgun is provided with a piston which is independently movable in a cylinder to drive the action of the gun rearwardly, a single cartridge stop normally retaining cartridges in a magazine and released by rearward motion of the action, and a carrier latch which slides rearwardly to release the carrier when the cartridge being chambered is fully disposed on the carrier, thereby permitting that cartridge to retain other cartridges in the magazine until the cartridge stop is restored to its cartridge blocking position. To chamber the cartridge, a rotatable breech block is rotated from its open to its locked position by axial motion of a bolt support extending through a cam slot in the bolt.

United States Patent [1 1 Tollinger 1 Sept. 118, W73

[ SEMI-AUTOMATIC SHOTGUN [75] Inventor: James Tollinger, Ithaca, NY.

[73] Assignee: Ithaca Gun Company, Incorporated,

Ithaca, NY.

[22] Filed: Nov. 9, 1971 [21] Appl. No.: 197,178

Related US. Application Data [62] Division of Ser. No. 864,446, Oct. 7, 1969, Pat. No.

[52] US. Cl. 89/33 B [51] Int. Cl. F4lc 13/00 [58] Field of Search 42/17, 2I; 89/33 R, 89/33 B, 191 R, 191 A, 192, 193

[56] References Cited UNITED STATES PATENTS 3,142,921 8/1964 Ruger 89/191 3,432,956 3/1969 Morrow 42/17 Primary Examiner-Stephen C. Bentley Attorney-Brumbaugh et al.

[57] ABSTRACT In the particular embodiment of the invention described herein, a semi-automatic shotgun is provided with a piston which is independently movable in a cylinder to drive the action of the gun rearwardly, a single cartridge stop normally retaining cartridges in a magazine and released by rearward motion of the action, and a carrier latch which slides rearwardly to release the carrier when the cartridge being chambered is fully disposed on the carrier, thereby permitting that cartridge to retain other cartridges in the magazine until the cartridge stop is restored to its cartridge blocking position. To chamber the cartridge, a rotatable breech block is rotated from its open to its locked position by axial motion of a bolt support extending through a cam slot in the bolt.

3 Claims, Ill Drawing Figures PATENTEUSEPI a ma SHEET 1 0F 5 E w l PATENTEU SEP18|975 3,759,135

SHEET 5 0F 5 SEMI-AUTOMATIC SHOTGIJN This is a division of application of Ser. No. 864,446 filed Oct. 7, 1969, now U.S. Pat. No. 3,680,433, issued Aug. 1, I972.

BACKGROUND OF THE INVENTION This invention relates to firearms and, more particularly, to a new and improved gas operated firearm characterized by simplicity of assembly and operation coupled with durability and precision of performance.

Heretofore, many arrangements have been devised for imparting expanding gas energy to the action of a gas operated firearm but in most instances the imparting mechanism and the action have suffered from excessive complexity of structure and assembly or limited durability of components. Similarly, previous arrangements for releasing cartridges from the magazine of a gas operated firearm and transporting them to the barrel breech have been complex in structure and subject to excessive wear or frequent breakage of one or more of the numerous components involved in the structure.

Accordingly, it is an object of this invention to provide a new and improved gas operated firearm which overcomes the above-mentioned disadvantages of the prior art;

Another object of the invention is to provide an improved gasoperated firearm characterized by simplicity of structure and operation, durability of components and improved reliability and accuracy.

BRIEF SUMMARY OF THE INVENTION In accordance with the invention a gas operated firearm having a cartridge magazine arranged for sequential release of individual cartridges in response to motion of an action assembly includes a piston supported for sliding motion, independent of the action assembly, in a cylinder which receives gases from the barrel of the firearm, the piston being movable thereby to impart actuating energy to the action assembly. According to another aspect of the invention; a carrier assembly positioned to receive cartridges from the magazine and transport them into chambering position in the receiver of the firearm includes a longitudinally slidable latch member arranged to be released upon engagement by a cartridge to initiate operation of the carrier assembly. A single stop member, normally retaining the outermost cartridge in the magazine is released by operation of the action assembly, the succeeding cartridge being retained within the magazine by engagement with the outermost cartridge until the carrier assembly is released to transport that cartridge to the chambering position.

To complete the cartridge chambering operation a breech bolt supported by the action assembly and formed with helically directed cam surfaces and axially spaced locking lugs, is rotated by axial motion of the action assembly, causing the locking lugs to engage corresponding lugs in a rearwardly extending portion of the barrel. Finally, the invention encompasses the combination of the foregoing structural and operational features to provide an overall gas operated firearm which is simplified in structure and has improved reliability.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. ll, comprising FIGS. IA, IB and IC taken together, is a fragmentary view in longitudinal section taken in a vertical plane through a representative gas operated semi-automatic shotgun arranged according to the invention, illustrating the components of the shotgun in the full recoil position of the action assemy;

FIG. 2 is a fragmentary view in longitudinal section, taken along the line 2-2 of FIG. 1B and looking in the direction of the arrows, further illustrating the cartridge stop and carrier latch arrangements of the shotgun;

FIG. 33 is a fragmentary view in longitudinal section, similar to that of FIG. ll, showing the shotgun with the carrier assembly in the cartridge chambering position;

FIG. d, comprising FIGS. IIA and III taken together, is a fragmentary view in longitudinal section taken along a vertical plane, illustrating the positions of certain of the shotgun components when the gun is in battery condition;

FIG. 5 is a cross-sectional view, taken along the line 5-5 of FIG. 1B and looking in the direction of the arrows;

FIG. 6 is a cross-sectional view taken along the line 6-45 of FIG. 1B and looking in the direction of the arrows;

FIG. 7 is a cross-sectional view taken along the line 7-7 of FIG. 3 and looking in the direction of the ar-. rows; and

FIG. 8 is a fragmentary sectional view taken along the line 8@ of FIG. IB and illustrating a representative breech bolt structure arranged in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the representative embodiment of the invention shown in FIGS. I and 2, a semi-automatic shotgun comprises a barrel III having a rearward extension Ill projecting into a receiver I2 which is affixed in the usual manner to a gun stock 113. A cartridge magazine l4, supported parallel to and below the gun barrel, contains a plurality of shells or cartridges I5 aligned endto-end for successive rearward movement into the receiver and upward transfer therein into chambering position by a vertically movable carrier I6. An action slide assembly I7 includes a tubular forward portion Id slidably surrounding the magazine I4, a pair of spaced parallel arms I9 and 2@ extending rearwardly therefrom into the receiver I2 and a bolt support Ell connected to the arms I9 and Zll and extending upwardly therefrom to support a breech bolt 22.

A compression spring 23 disposed within a cylindrical housing 24 within the gun stock I3 urges the entire action assembly I7 forwardly by way of a plunger 25 and a link member 25, the link being attached by a pivot 27 to the bolt support Ell. The receiver also includes a buffer 28, composed of nylon or similar shock absorbing material, which is engaged by the bolt 22 to absorb the impact of the action assembly at the end of its rearward motion.

The rearward motion of the action assembly is effective to cock the hammer 29 of the gun in a conventional manner, the hammer being released to fire the gun by the trigger dd which is pivotally supported in a trigger housing Elli. In addition, the carrier In, which is supported for pivotal motion in the receiver by a pivot 32, carries a rotary dog 33 which is urged by a spring assembly 34 about its pivot 35 in the clockwise direction as viewed in FIG. 1. As the action slide moves rearwardly it rotates the dog 33 counterclockwise so that, when the carrier 16 is released in the manner described below, the spring 34 causes the dog to rotate clockwise, lowering the rearward end of the carrier and raising the forward end so as to transport a cartridge to chambering position. When the dog 33 is released by forward motion of the action assembly the spring 34 urges the rear end of the carrier 16 upwardly, causing the forward end to be restored to the cartridge receiving position.

In accordance with the invention, the action slide assembly 17 is driven rearwardly after each firing operation by a piston member which is movable within a gas cylinder independently of the action assembly. As best seen in FIGS. 1 and 4, a gas cylinder 36, affixed to the barrel 10, is closed at its forward end and communicates with the bore of the barrel through a gas intake port 37. A piston 38 is slidably supported within the cylinder 35 and carries a nylon buffer member 39 for engagement with the front wall of the magazine housing 14 in its rearmost position shown in FIG. 1. A gas exhaust port 40 is positioned in the cylinder 35 to be exposed with piston 38 in its rearward position. As is evident from FIG. 4, the piston engages the forward end 41 of the action assembly when the gun is in the battery condition and the piston is at the forward end of the cylinder, thereby assuring prompt initiation of the rearward motion of the action upon firing of the gun.

As the piston 38 moves rearwardly, the entire operating energy is imparted to the action slide assembly before the gas exhaust port 40 is exposed, thereby permitting accurate control of the energy imparted to the action slide assembly for its operation during the first portion of the piston stroke and assuring complete venting of the exhaust gases during the remainder of the stroke. In this way, the energy imparted to the action slide assembly is made substantially independent of variations in gas pressure in the barrel during any particular cycle of operation or from one cycle of operation to the next so that the shotgun components are protected from excessive strain while sufficient energy for positive action is assured.

Within the cartridge magazine 14 a magazine spring 43 urges a cartridge follower 44 in the rearward direction, causing the cartridges 15 to move rearwardly therein as the preceding cartridges are released in succession. Whenever a cartridge 15 is being raised by the carrier 16 to the chambering position, as illustrated in FIG. 3, and while the gun is in the battery position, as shown in FIG. 4, the rearmost cartridge in the magazine is held in position by engagement with an elongated cartridge stop member 45. As best seen in FIGS. 2, 4, and 7, the cartridge stop is supported by a pivot 46 within a longitudinal recess 47 in the right hand wall of the receiver 12, the forward end of the stop member being biased outwardly by a coil spring 48.

Along its inner surface the stop member is formed with an inclined ramp 49 terminating in a forwardly facing abutment 50 so that when the magazine is being loaded the rim of each cartridge can be moved past the stop by deflecting it outwardly away from the magazine axis, after which the cartridge is retained in the magazine by engagement of its rim with the abutment as shown in FIGS. 3 and 4.

To retract the stop member 45 when a shell is to be released from the magazine a cam member 51 projecting upwardly from the forward end of the stop member is shaped so as to be deflected outwardly into a recess 52 in the receiver by a downwardly projecting portion 53 of the right hand action bar 19, as illustrated in FIGS. 1 and 5, whenever the action assembly is in its rearmost position. To assure positive engagement of the abutment 50 with the rim ofa cartridge when in the stopping position, a cartridge guide 54, mounted in the opposite wall of the receiver 12, prevents the end of the rearmost cartridge in the magazine from being tilted away from the stop.

In response to the urging of the magazine spring 43 the rearmost cartridge, when released by deflection of the stop member 45, moves rearwardly onto the carrier 16 as illustrated in FIGS. 1 and 2. To hold the carrier in the cartridge receiving position at all times except when the magazine is being loaded or when a cartridge is being raised and chambered, a carrier latch member 55 is supported for sliding motion parallel to the axis of the gun by two rearwardly extending arms 56 received in corresponding grooves 57 in the trigger block 58. A compression spring 59 urges the latch member forwardly within a central opening 60 in the carrier 16 and an aperture 61 in the latch member receives a rearward projection 61 extending from the center of the carrier a short distance into the opening 60. In this way, the carrier is nonnally prevented from moving upwardly in response to external pressure or the spring bias of the dog 33 when pivoted rearwardly by the action assembly as shown in FIG. 1.

At its upper end the latch member 55 has a forwardly directed projection positioned to engage the rear surface of a cartridge 15 just below its center as illustrated in FIGS. 1 and 2. Thus, when a cartridge 15 being loaded onto the carrier is urged rearwardly by the magazine spring beyond the position shown in FIGS. 1 and 2, the carrier latch member 55 will move rearwardly against the bias of the latch spring 59, releasing the projection 62 from the aperture 61 and permitting the carrier to be moved upwardly by the rotary bias of the spring 34 on the dog 33. The sliding support arrangement for the carrier latch assures improved durability and provides structural simplicity as contrasted with other latch support mechanisms, such as pivotal mountings.

During this entire operation, the rearmost cartridge remaining in the magazine is held forwardly of the abutment 50 on the stop member 45 by the forward end of the cartridge which is being chambered. As a result there is always sufficient time for the stop member to be restored to its blocking position before the carrier is raised to remove the cartridge from engagement with the cartridge remaining in the magazine. Consequently, there is no necessity for any complex double stop arrangement to prevent more than one cartridge from being supplied to the carrier during one operation. In addition, because the carrier 16 can not be raised until the cartridge being chambered has engaged the carrier latch, it is not necessary to provide an excessively strong magazine spring or any forward motion stop to prevent cartridges in the magazine from moving forward when the previously chambered cartridge is tired. Moreover, because the carrier latch projects downwardly through the carrier opening 16 it may be released manually, permitting the carrier to be raised for loading of the magazine. For this purpose, the lower portion 67 of the latch member may be knurled to facilitate engagement and operation by the thumb of the user.

As illustrated in FIGS. 5, 6, and 7, the barrel extension 11 is approximately semi-circular in shape, corn mencing at an edge 68 adjacent to the top ofa cartridge ejection opening 69 in the receiver and terminating at an edge 70 disposed below the barrel axis on the opposite side of the receiver. As best seen in FIGS. 1 and 3, the edge 70 of the barrel extension has three rectangular recesses 71 spaced in the axial direction by approximately equal segments 72 of the barrel extension. Corresponding lugs 73 extending outwardly from the breech bolt 22, as shown in FIG. 8, are positioned to be received in the recesses 71 when the bolt is in battery position, thereby locking the bolt securely.

To accomplish the bolt locking in a convenient and effective manner, the bolt 22 is formed in its lower surface with a generally longitudinal slot 74 having opposed helically directed surfaces 75 and 76 and arranged to receive the upwardly projecting bolt support 21 of the action assembly. Accordingly, as the action assembly moves forwardly from the position shown in FIGS. 1 and 6, retention of the bolt support 21 at the rear of the slot 74 prevents rotation of the bolt and permits the bolt projections 73 to move below the edge 70 of the barrel extension. When the bolt reaches its forwardmost position, the lugs 73 are aligned with the corresponding recesses 71 in the barrel extension, thereby permitting the bolt to rotate to the locked position shown in FIG. 3 as the action assembly moves the bolt support forwardly in the slot 74 and the support 21 engages the forward helically directed surface 75. Upon rearward motion of the action assembly, the helically directed surface 76 is engaged by the bolt support 21, causing the bolt to rotate in the opposite direction to unlock the bolt lugs 73 from the barrel recesses 71.

Within the bolt 22 an axially slidable firing pin 77 is urged rearwardly by a spring 78 and normally projects beyond the rear end of the bolt so as to be engaged by the hammer 29 when the gun is fired. In addition, a nylon buffer 79 is positioned within the bolt to absorb energy transmitted from the action assembly through the bolt support 21 at the end of its rearward motion.

In operation, therefore, with the gun in battery position, as shown in FIG. 3, the chambered cartridge is fired, causing gas to pass from the barrel through the port 37 into the cylinder 35 and drive the piston 38 and the action slide assembly engaged thereby in the rearward direction. After the forward end of the piston exposes the exhaust port 40 and the piston is stopped by the buffer 39, the action assembly continues rearwardly. When the action assembly reaches its rearmost position, as shown in FIGS. 1 and 2, the downwardly projecting portion 53 of the action bar 119 deflects the stop member 45 to release the rearmost cartridge from the magazine 114. That cartridge, driven rearwardly by the magazine spring d3, engages the carrier latch projection 65 to disengage the latch from the carrier 116.

When the latch 55 is released, the carrier is moved upwardly by rotary motion of the dog 33 under the urging of the spring 34, which moves the components to the position shown in FIG. 3. This releases the action assembly and it commences its forward motion in response to the urging of the action of spring 23. When the carrier is raised, the action assembly moves the bolt support 2E forwardly, causing the bolt 22 to chamber the elevated cartridge and rotating the bolt into the locked position illustrated in FIG. 3. With the dog 33 released by forward motion of the bolt support 231, the carrier 16 is pivoted downwardly to the latched position by the spring 34. At the same time, the piston 35 is carried by the forward end 4B of the action assembly to its forward position in the cylinder 35 in readiness for the next cycle of operation.

I claim:

ll. In a gas operated firearm having a barrel, a receiver, a magazine for supplying cartridges in succession to the receiver, carrier means within the receiver for transferring cartridges received from the magazine into chambering position, bolt means for chambering cartridges and closing the breech end of the barrel, and action slide means for driving the bolt means, the improvement comprising carrier latch means slidably supported within the receiver for longitudinal sliding motion therein and including means forming an aperture, a member projecting from the carrier means and normally extending through the aperture to retain the carrier means in cartridge-receiving position, the latch means responsive to motion of a cartridge from the magazine onto the carrier means to release the carrier means for transfer of the cartridge to chambering position and having a portion for enabling a user to manually disengage the member from the aperture.

2. A gas operated firearm according to claim ll wherein the latch means comprises a member extending generally perpendicularly to the carrier means and a projecting element extending from the member toward the magazine in position to be engaged by the end of a cartridge received on the carrier.

3. A gas operated firearm according to claim ll wherein the carrier means comprises a member supported for pivotal motion and including a rotatable dog pivotally attached to the member adjacent to one end thereof, and a double-acting spring tending to rotate the dog about its pivot axis and to rotate the carrier member about its pivot axis.

fi t i t t 

1. In a gas operated firearm having a barrel, a receiver, a magazine for supplying cartridges in succession to the receiver, carrier means within the receiver for transferring cartridges received from the magazine into chambering position, bolt means for chambering cartridges and closing the breech end of the barrel, and action slide means for driving the bolt means, the improvement comprising carrier latch means slidably supported within the receiver for longitudinal sliding motion therein and including means forming an aperture, a member projecting from the carrier means and normally extending through the aperture to retain the carrier means in cartridge-receiving position, the latch means responsive to motion of a cartridge from the magazine onto the carrier means to release the carrier means for transfer of the cartridge to chambering position and having a portion for enabling a user to manually disengage the member from the aperture.
 2. A gas operated firearm according to claim 1 wherein the latch means comprises a member extending generally perpendicularly to the carrier means and a projecting element extending from the member toward the magazine in position to be engaged by the end of a cartridge received on the carrier.
 3. A gas operated firearm according to claim 1 wherein the carrier means comprises a member supPorted for pivotal motion and including a rotatable dog pivotally attached to the member adjacent to one end thereof, and a double-acting spring tending to rotate the dog about its pivot axis and to rotate the carrier member about its pivot axis. 